Advancements in communication technologies have permitted significant improvements in the manners by which data can be communicated between a sending and a receiving station.
For instance, in radio communications, advancements in digital communication techniques are permitted the introduction of, and popularization of, new types of communication systems. For example, cellular communication systems which utilize digital communication technologies have been installed in many areas and are widely utilized. Conventional, cellular communication systems typically transmit synchronous voice and other data.
Advancements in communication technologies have also facilitated the decentralization of computer systems. Processing devices can be distributed at separate locations and connected together by network connections. When connected together, the processing devices form LANs (local area networks). Groups of LANs can be connected together to form WANs (wide area networks).
A packet-data protocol, ATM (asynchronous transfer mode), is a standard protocol frequently utilized in data communications. In ATM communications, data to be communicated between a sending a receiving station is formatted into fixed-length cells. Groups of the cells form packets of data which are transmitted between the sending and receiving stations to effectuate communication therebetween.
The advancements in communication technologies have also permitted the merging of radio and network-connected communication systems. For instance, it is possible for a terminal device, such as a portable computer, to be coupled by way of a radio link to network infrastructure of a radio communication system and, in turn, by way of the network, or other wireline connection to a data terminal. To communicate between the terminal device and the data terminal, the terminal device can utilize the ATM protocol, and the ATM cells forming the packets of data are transmitted over the radio link between the terminal device and the data terminal.
The communication capacity of a radio communication system is sometimes limited by the frequencies allocated to form radio channels operable therein. As radio communications are increasingly utilized, both for conventional communication of synchronous data and also for the communication for ATM-type data, proposals have been set forth to allocate additional frequency bands for such communications.
For instance, proposals have been set forth to utilize frequencies available in the 5 GHz frequency band both for the communication of synchronous data and also for the communication of asynchronous, such as ATM, data. Viz., the same radio link shall be used for both the communication of asynchronous data and also the communication of synchronous data. Therefore, different types of radio networks must co-exist in one frequency band.
Synchronous communications can typically be effectuated by narrowband techniques. And, receivers operable to receive synchronous data communicated in such manners need only receive and process narrowband signals. Conversely, at least some asynchronous communications are effectuated by broadband techniques. For example, multi-media communications typically are effectuated utilizing broadband techniques.
A narrowband receiver typically requires less power and processing capacity than a broadband receiver as a broadband receiver must be constructed to receive data over a broad range of frequencies.
If both narrowband, synchronous and broadband, asynchronous communications are to be effectuated over a common frequency band, a formatting scheme which does not require receivers operable to receive only synchronous communications to receive communication signals over a broad frequency range.
That is to say, radio receivers operable in radio networks which communicate only synchronous, narrowband data need not be constructed to receive also the broadband data, such as that which might be communicated pursuant to ATM, or other asynchronous data transmissions.
It is in light of this background information related to the communication of synchronous and asynchronous data that the significant improvements of the present invention have evolved.